1. Field of the Invention
The present invention relates to a zero insertion force (ZIF) electrical connector, and particularly to a ZIF electrical connector for electrically connecting an electronic package such as a central processing unit (CPU) with a circuit substrate such as a printed circuit board (PCB). The invention relates to a copending application Ser. No. 10/839,838 filed on May 5, 2004.
2. Description of the Prior Art
Zero insertion force (ZIF) electrical connectors are well known in the computer industry and are used for electrically connecting electronic packages such as central processing units (CPUs) with circuit substrates such as printed circuit boards (PCBs). Pertinent examples of such connectors are disclosed in U.S. Pat. Nos. 6,544,065, 6,533,597, 6,508,659, 6,482,022, 6,406,317 and 6,280,223.
Normally, a conventional ZIF electrical connector comprises a base soldered to and electrically connected with a PCB, a cover slideably mounted on the base and having a CPU attached thereon, and an actuating device for actuating the cover to slide along the base. The CPU has a plurality of leads extending outside a bottom surface thereof and arranged in a rectangular array. The cover has a plurality of through holes arranged corresponding to the leads of the CPU. The base defines a plurality of receiving passageways arranged corresponding to the leads of the CPU, too. Each receiving passageways receives an electrical terminal therein. When the CPU socket is in an open position, the leads of the CPU extend through the corresponding through holes of the cover and are received in the corresponding passageways of the base. The leads of the CPU do not contact the corresponding electrical terminals, thereby the CPU is attached on the CPU socket with zero insertion force. The actuation device comprises an operation lever to facilitate manual handling by a user. When the operation lever is rotated toward and locked in a closed position, the cover is correspondingly driven to slide along the base, and the CPU socket reaches a closed position. The actuation device thus pushes the leads of the CPU into mechanical and electrical engagement with the electrical terminals.
Prior to attachment of the CPU onto the socket, the operation lever may be inadvertently positioned midway between the open position and the closed position. When the CPU is attached to the socket, the leads of the CPU are inserted directly into the electrical terminals of the base. The leads of the CPU and the terminals in the base are liable to be damaged, in which case the electrical engagements between the leads of the CPU and the corresponding electrical terminals may be impaired.
Hence, an electrical connector having an improved actuation device is desired to overcome the disadvantages of the related art.